<template>
  <div class="my-tag">
    <input 
        v-if="isEdit"
        v-focus
        ref="inp"
        class="input"
        type="text"
        placeholder="输入标签"
        :value="value"
        @blur="isEdit = false"
        @keyup.enter="handleEnter"
    />
    <div 
        v-else 
        @dblclick="handleClick"
        class="text">
        {{value}}
    </div>
  </div>
</template>

<script>
export default {
    data() {
        return {
            isEdit: true
        }
    },
    methods: {
        handleClick() {
            //双击后，切换到显示状态
            this.isEdit = true
            //等dom更新完了，再获取焦点
            this.$nextTick(() => {
                this.$refs.inp.focus()
            })
            
        },
        handleEnter(e) {
            //非空处理
            if(e.target.value.trim() === '') return alert('标签内容不能为空')
            //子传父，将回车时输入框的内容提交给父组件更新
            //由于父组件是v-model触发事件，需要触发input事件
            this.$emit('input',e.target.value)
            //提交完成，关闭输入状态
        }
    }
}
</script>

<style lang="less" scoped>
 .my-tag {
    cursor: pointer;
    .input {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      width: 100px;
      height: 40px;
      box-sizing: border-box;
      padding: 10px;
      color: #666;
      &::placeholder {
        color: #666;
      }
    }
  }
</style>